Alamut Castle is a historic fortress located in the Alborz Mountains of northern Iran. Built in the 9th century, it served as a strategic stronghold for the Nizari Ismailis, a sect of Islam. The castle is renowned for its dramatic cliffside location and impressive architecture, which includes thick walls and narrow passages. The castle gained fame in the 11th century under the leadership of Hassan-i Sabbah, who established it as the center of the Assassins sect. Alamut Castle played a significant role in the political and military history of the region, influencing various conflicts during the Middle Ages.